Passenger protection systems, such as restraint systems or airbag systems, include a controller and include at least one sensor, and an integrated driver circuit, each being connected to the controller. The driver circuit controlled by the controller triggers the restraint system. An airbag system includes a squib as a triggering element, the squib being connected to the driver arrangement. The squib is ignited—and the airbag is triggered—by driving a current provided by the driver circuit through the squib.
Driver circuits in safety systems, such as passenger protection system, regularly need to be checked for errors that may affect proper function of the driver circuit and, therefore, the protection system. A diagnostic function for regularly checking the driver arrangement may be implemented in the controller. However, diagnostic routines running on the controller considerably influence the workload of the controller. In some systems diagnostic functions make up to 50% of the controllers workload.
There is therefore a need to reduce the workload resulting from diagnostic functions of a controller in an arrangement that includes an integrated driver circuit.